Technical
Manual
Temperature
Controller
SCN
‐
RT1
MDT technologies GmbH •
51766 Engelskirchen • Papiermühle 1
Tel.: +49-2263-880 • Fax: +49-2263-4588 • [email protected] • www.mdt.de
35
Chart
35:
PI
control
switching
(PWM)
At
the
pulse
width
modulation,
the
controller
switches
the
control
value
according
to
the
calculated
value
of
the
continuous
control
on
and
off.
Thereby
the
control
watches
also
the
adjusted
cycletime.
So
the
control
value
is
converted
to
a
pulse
width
modulation
with
only
the
two
conditions
“0”
and
“1”.
4.6.3.1
PWM
cycletime
The
cycletime,
„PWM
cycletime“,
serves
the
controlling
for
calculating
the
length
of
the
on
‐
pulse
and
the
off
‐
pulse.
This
calculation
occurs
at
the
base
of
the
calculated
continuous
value
in
percent.
One
PWM
cycle
contains
the
time,
which
elapses
from
one
switching
on
point
to
the
other.
Example:
If
a
control
value
of
75%
is
calculated
and
a
cycletime
of
10min
is
adjusted,
the
control
value
will
be
switched
on
for
7,5min
and
switched
off
for
2,5min.
In
principle
you
can
say
each
carrier
the
system,
each
bigger
the
cycletime.
Cooling
system
Split
Unit
(4K/90min)
Cooling
ceiling
(5K/240
min)
Adjustment
via
control
parameter
Adjustment
of
the
used
cooling
system
Individual
parameterization
available
by
“Adjustment
via
control
parameter”
Proportional
range
(K)
1K
‐
8K
[2K]
By
choosing
heating/cooling
system
as
“Adjustment
via
control
parameter”,
the
proportional
range
can
be
parameterized
freely
Reset
time
(min)
15min
–
210
min
[150
min]
By
choosing
heating/cooling
system
as
“Adjustment
via
control
parameter”,
the
reset
time
can
be
parameterized
freely
Send
control
value
cyclic
Disable,
1
min,
2min,
3min,
4
min,
5min,
10min,
15min,
20min,
30min,
40min,
50min,
60min
[Disable]
Activation
of
cyclic
sending
of
the
control
value
with
adjustment
of
the
cyclic
time
Use
additional
level
No
Yes
Activation
of
an
additional
level
available,
only
for
heating
(4.5.6)
PWM
cycletime
(min)
5min,
10min,
15min,
20min,
25min,
30min
[10min]
describes
the
whole
time
off
an
on
‐
pulse
and
an
off
‐
pulse
